A Naked-eye based Strategy for Semiquantitative Immunochromatographic Assay

• 作 者: Zhang DH Li PW Zhang Q Li R Zhang W Ding XX Li CM
• 机 构: Oil Crops Research Institute,Chinese Academy of Agricultural Sciences,Wuhan 430062,China;Key Laborat
• 出 处: 中国作物学会油料作物专业委员会第七次会员代表大会暨学术年会
• 发表日期: 2013年12期
• 关键词: Semiquantitative Immunochromatographic assay Naked-eye On-site

　　It is critical to develop a cost-effective quantitative/semiquantitative assay for rapid diagnosis and on-site detection of toxic or harmful substances.Here, a naked-eye based semiquantitative immunochromatographic strip (NSI-strip) was developed, on which three test lines (TLs, TL-Ⅰ, TL-Ⅱ and TL-Ⅲ) were dispensed on a nitrocellulose membrane to form the test zone.Similar as the traditional strip assay for small molecule, the NSI-strip assay was also based on the competitive theory, difference was that the analyte competed three times with the capture reagent for the limited number of antibody binding sites.After the assay, the number of TLs developed in the test zone was inversely proportional to the analyte concentration, thus analyte content levels could be determined by observing the appeared number of TLs.Taking aflatoxin B1 as the model analyte, visual detection limit of the NSI-strip was 0.06ng/mL and threshold concentrations for TL-Ⅰ-Ⅲ were 0.125, 0.5, and 2.0ng/mL, respectively.Therefore, according to the appeared number of TLs, the following concentration ranges would be detectable by visual examination :0-0.06ng/mL (negative samples), and 0.06-0.125ng/mL, 0.125-0.5ng/mL, 0.5-2.0ng/mL and > 2.0ng/mL (positive samples).That was to say, compared to traditional strips the NSI -strip could offer more parameter information of the target analyte content.In this way, the NSI-strip improved the qualitative presence/absence detection of traditional strips by measuring the content (range) of target analytes semiquantitatively.